Propynyl benzyl ethers as insecticidal agents

ABSTRACT

Propynyl benzyl ethers having juvenile hormone-like activity which are 4-halogen, lower alkyl, lower alkoxy or propynyloxy substituted or 3,4-lower alkylenedioxy substituted and which can also be 3,5- and/or Alpha -substituted, and insecticide compositions that include at least one propynyl benzyl ether and that can also include a conventional insect-poison.

United States Patent Chodnekar et al.

[4 1 Sept. 23, 1975 PROPYNYL BENZYL ETHERS AS INSECTICIDAL AGENTS Inventors: Madhukar Subraya Chodnekar,

Basel; Albert Pfiffner, Pfaffliausen; Norbert Rigassi, Arlesheim; Ulrich Schwieter, Reinach; Milos Suchy, Pfaffhausen, all of Switzerland Assignee: Hoffmann-La Roche Inc., Nutley,

Filed: Dec. 26, 1973 Appl. No.: 427,765

Related US. Application Data Division of Ser. No. 235,037, March 15, 1972, Pat. No. 3,840,604.

Foreign Application Priority Data Mar. 19, 1971 Switzerland 4121/71 US. Cl. 424/341; 424/186; 424/200; 424/300 Int. CI. A01N 9/02; AOIN 9/08; AOIN 9/24; AOIN 9/36 [58] Field of Search 424/340, 341; 260/613 D [56] References Cited UNITED STATES PATENTS 3,338,950 8/1967 Seki et al. 260/613 D X OTHER PUBLICATIONS Borkovec, Insect Chemosterilants, 1966, pp. 61-63.

Primary ExaminerA1bert T. Meyers Assistant Examiner-Allen J. Robinson Attorney, Agent, or FirmSamue1 L. Welt; Jon S. Saxe; Richard A. Gaither [57] ABSTRACT 5 Claims, No Drawings PROPYNYL BENZYL ETHERS AS INSECTICIDAL AGENTS This application is a division of US. Pat. application Ser. No. 235,037, filed Mar. 15, I972, now US. Pat. No. 3,840,604.

BACKGROUND OF THE INVENTION Many conventional insect-poisons, such as the carbamates, the pyrethrins and the chlorinated hydrocarbons, although highly lethal to numerous insects, cannot be used indescriminately. Despite their value for protecting foodstuffs, feeds, textiles and plants, these insect-poisons tend to remain indefinitely in the environment after being used. They are not naturally degraded, and by remaining undegraded in the environment, their lingering residues tend to find their way into foods intended for human or cattle consumption. Moreover, because apparently many of these insectpoisons are not quantitatively degraded by mammalian organisms, their use can lead to the indirect injury of humans or other mammals. Thus, the decision to use many conventional insect-poisons cannot be made without some significant reservations. There has been a need, therefore, for effective insect-poison compositions having a reduced tendency to linger in the environment, to contaminate food and to resist degradation in mammals.

SUMMARY OF THE INVENTION In accordance with this invention, it has been found that propynyl benzyl ethers of the formula:

wherein R is individually hydrogen, halogen, lower alkyl, lower alkoxy or propynyloxy and R is individually halogen, lower alkyl, lower alkoxy or propynloxy or R and R taken together form a lower alkylenedioxy group; R and R are hydrogen or lower alkyl; and R is hydrogen or lower alkoxy; are useful in killing and preventing the proliferation of insects by upsetting their hormonal balance.

In accordance with another embodiment of this invention, insecticide compositions are provided which include at least one of the propynyl benzyl ethers and which can also include a conventional insect-poison.

The propynyl benzyl ethers of formula I are prepared by reacting an alcohol of the formula:

wherein R R R R and R are as above; with a halide of the formula:

CH I CCH -X wherein X is chlorine, bromine or iodine.

III

DETAILED DESCRIPTION OF THE INVENTION As used throughout this application, the term insect-poison comprehends a compound or a combination of compounds which kill, disable or repel insects by either their chemical or physical effects upon the insects systems. In the insecticide compositions of this invention, any conventional insect-poison can be utilized. Among the preferred insect-poisons are the carbamates, pyrethrins, chlorinated hydrocarbons, phosphoric acid esters, and thio-phosphoric acid esters. Among the carbamates, especially preferred are the following:

I-naphthyl-methylcarbamate (Sevin);

m-( I-methylbutyl)-phenyl methylcarbamate;

m-( l-ethyl-propyl)phenyl methylcarbamate;

3-methyl-5-isopropyl-phenyl methylcarbamate;

m-{[(dimethylamino)-methylene]-amino}-phenyl methylcarbamate; and

l-dimethylcarbamoyl-5-methyI-3-pyrazolyl ylcarbamate Among the pyrethrins, especially preferred are the following:

pyrethrum, particularly pyrethrin I and II, and jasmolin II; 2,2-dimethyI-3-(2-methylpropenyl)- cyclopropanecarboxylic acid I-cyclohexene-l,2- dicarboximido-methyl ester; 2,2-dimethyl-3-(2-methylpropenyl)- cyclopropanecarboxylic acid methyl ester; and 2-aIlyl-4-hydroxy-3-methyl-2-cyclopenten- I -one esterified with a mixture of cis and trans 2,2- dimethyl-3-(2-methylpropenyl)- cyclopropanecarboxylic acid (Allethrin).

Among the halogenated hydrocarbons, especially preferred are the following:

l,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydrol ,4-endoexo-5,8-dimethano-naphthalene; octachloro-camphor;

l l l -trichIoro-2,2-bis( p-chIorophenyl)-ethane;

l,2,3,4, I 0, I O-hexachloro-6,7-epoxyl ,4,4a,5,6,7,8,8a-octahydro-I ,4-endo-endo-5,8- dimethano-naphthalene; 1,2,3,5,6,7,8,8-octachloro-2,3,3a,4,7,7a-hexahydro- 4,7-methano-indene; l,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-

endomethano-indene; 1,1 ,1-trichloro-2,2,bis-(p-methoxyphenyl)-ethane (Methoxychlor);

hexachloro-cyclohexane;

l,2,3,4, I 0, I O-hexachloro-6,7-epoxy- I ,4,4a,5,6,7,8,8a-octahydro-I ,4-endo-exo-5 ,8- dimethano-napthalene;

1,1 l -trichloro-2,2-bis( p-chlorophenyl )ethanol (Kelthane);

I, I -dichloro-2,2-bis-( p-ethylphenyl )-ethane;

l ,1-dichloro-2,2-bis-(p-chlorophenyl)-ethane;

l,2-dibromo-3-chloro-propane;

1,2-dibromo-ethane; and

methyl bromide.

Among the phosphoric acid esters, especially preferred are the following:

2-carbomethoxy-l-prop-Z-enyl dimethyl phosphate;

l,2 dibromo-2,Z-dichloroethyl dimethyl phosphate;

dimethand II, cinerin I 5-benzyl-3-furyl- 1chloro-diethylcarbamoyl-l-prop-2-enyl phosphate;

tetraethyl pyrophosphate;

tetra-N-propyl dithiono-pyrophosphate;

0,0dimethyl-O-Z,Z-dichlorovinyl-phosphate;

0,0-dimethyl-O-[ l-methyl-2-( l-phenyl-carbethoxy)-vinyl]-phosphate; and

0,0-dimethyl-( lhydroxy-2,2,2-trichloroethyl)- phosphonate.

Among the thiophosphoric acid esters, especially 1O preferred are the following:

S-[1,2-bis-(carbethoxy)-ethyl]-0,0-dimethyldithiophosphate (Malathion); 0,0-diethyl-O-(2-isopropyl-4-methyl-6-pyrimidyl)- thiophosphate; 0,0-dimethyl-O-(p-nitrophenyl)-thiophosphate; 0,0-diethyl-O-(p-nitrophenyl)-thiophosphate; 0,0-dimethyl-S-[4-oxo-2,2,3benzotriazin-3-(4H)- yl-methyll-dithiophosphate; 0,0-diethyl-S-(Z-ethylthio)-ethyl-dithiophosphate;

0,0-dimethyl-S-( 2-ethylthio)-ethyl-thiophosphate; 0,0-dimethyl-O-(Z-ethylthio)-ethyl-thiophosphate. 0,0-diethyl-S-(2,5-dichlorophenyl-thiomethyl)- dithiophosphate; 0,0-dimethyl-S-(N-methylcarbamoyl-methyl)- dithiophosphate; 2,3-p-dioxandithio dithiophosphate); 0,0,0',O-tetraethyl-S,Smethylene-bis-(dithi0- phosphate);

and

S-{[p-chlorophenyl )thio]-methyl }-0,0-diethyldithiophosphate.

Among other preferred insect-poisons, especially preferred are the following:

N,N-dimethyl-N( 2-methyl-4-chlorophenyl)- formamidine;

2-(p-tert.butylphenoxy)-isopropyl 2-chloroethyl sulphite;

p-chlorophenyl 2,4,5-trichlorophenyl sulphone;

6,7,8,9, l 0, l O-hexachloro-l ,5,5a,6,9,9a-hexahydro- 6,9-methano-2,4,3benzodioxathiepine 3-oxide;

N-( 1,l,2,2-tetrachloroethyl-sulphinyl)-cyclohex-4- ene-l ,2-dicarboximide:

2-dodecanoic acid 2-thiocyanato-ethyl ester;

crotonic acid 2-( l-methyl-heptyl)-4,6-dinitro-phenyl ester;

N-trichloro-methylthio-cyclohex-4-ene-l ,2-

dicarboximide;

N-trichloro-methylthio-phthalimide;

3,4-methylenedioxy-6-propyl-benzyl butyl diethylene glycol ether; and

rotenone.

As also used throughout this application, the term propynyl benzyl ether comprehends a propynyl benzyl ether of formula I which has juvenile hormone-like activity. The juvenile hormonelike activity of the propynyl benzyl ethers interferes with insects hormonal systems, causing their transformation to the imago, their laying of viable eggs and the development of their eggs to be disrupted. These disruptions, which are the characteristics ofjuvenile hormone activity, effectively prevent affected insects from maturing and proliferat 65 mg.

Among the preferred propynyl benzyl ethers are the compounds of the formula:

dimethyl S,S'-bis-(0,0-diethyltoluene. As further used throughout this application, the term lower alkyl comprehends straight chain and branched chain saturated aliphatic groups having I to 6 carbon atoms, preferably methyl or ethyl. As used herein, the term lower alkoxy comprehends alkoxy groups having 1 to 6 carbon atoms, preferably methoxy and ethoxy. As also used herein, the term lower alkylenedioxy comprehends alkylenedioxy groups containing l to 4 carbon atoms, preferably 1 to 3 carbon atoms, particularly methylenedioxy and ethylenedioxy. As further used herein, the term halogen or halo comprehends all four halogens, fluorine, chlorine, bromine and iodine, unless otherwise stated.

The propynyl benzyl ethers of formula l are useful in the control of invertebrate animals, such as arthropods and nematodes, especially against various kinds of insects. For example, they are active against Diptera such as house flies, fruit flies (Drosphila melanogaster), midges and stable flies, Lepidoptera such as cabbage looper (Trichoplusia ni), bud moth, lazy bombyx, owlet moth and owlet caterpillar, and Coleoptera such as alfalfa weevils (Hypera postica), confused flour beetles (Tribolium confusum), aphids, Colorado beetles, spider-mites and Prodenia litura.

The propynyl benzyl ethers are also practically nontoxic to vertebrates. The toxicity of the compounds is greater than 1,000 mg/kg body weight. Moreover, these compounds are readily degraded and the risk of accumulation is therefore excluded. Therefore, these compounds can be used without fear or danger in the control of pests in animals, plants, foods, and textiles.

Generally, in controlling invertebrate animals, the propynyl benzyl ethers are applied to the material to be protected, e.g., foodstuffs, feeds, textiles and plants, in concentrations of from about l0- to 10" gm/cm of the material to be protected. Generally, it is preferred to utilize the propynyl benzyl ethers in a composition with a suitable inert carrier. Any conventional inert carrier can be utilized.

The propynyl benzyl ethers can, for example, be used in the form of emulsions, suspensions, dusting agents, solutions or aerosols. In special cases, the materials to' be protected can also be directly impregnated with the appropriate compound or with a solution thereof.

. suitable for spraying on the material to be protected.

Such solutions should contain the ether in a concentration of 0.01% by weight to 0.5% by weight, preferably 0.1% by weight. These solutions can be prepared by dissolving or dispersing these compounds in a solvent, such as mineral oil fractions, cold tar oils, oils of vegetable or animal origins, hydrocarbons such as napthalenes, ketones such as methyl ethyl ketone, and chlorinated hydrocarbons such as tetrachloroethylene and tetrachlorobenzene. These compounds can also be provided in forms suitable for dilution with water to form aqueous liquids such as, for example, emulsion concentrates, pastes or powders. The propynyl benzyl ethers above can be combined with solid-carriers for making, dusting or strewing powders such as, talc, kaolin, bentonite, calcium carbonate, and calcium phosphate. The compositions containing the compounds of formula I above can also contain, if desired, emulsifiers, dispersing agents, wetting agents, and/or other active .substances such as fungicides, bactericides, nematocides, fertilizers and the like. The materials which are to be protected act as bait for the insect. In this manner, the insect, by contacting the material impregnated with the propynyl benzyl ether, also contacts the ether itself.

In addition, it has been surprisingly found that the activity of a conventional insect-poison can be increased by a factor of about two to ten and more by combining the insect-poison with a propynyl benzyl ether. The propynyl benzyl ether and the insect-poison, when combined in an insecticide composition, provide up to the same degree of insectidical activity with l0%50% of the previously used amounts of insect-poison, thereby reducing the residue of insect-poison in the environment to a tolerable degree. Such a composition possesses an additional advantage, i.e., after the abatement of the insecticidal action of the insect-poison, the juvenile hormone action comes to the fore so that the sequence of generations is interrupted and the pests are indirectly killed.

Thus, the rapidly commencing action of the insectpoisons can be synergistically augmented by the juvenile hormone action of the propynyl benzyl ethers, which disturbs the subsequent re-building of the insect population, thereby permitting the intervals between sprayings of the insecticide composition to be extended.

The proportions of the two components of the combined insecticide composition, in accordance with this invention, can vary within wide limits according to the purpose of use, the mode of application, the pests to be controlled and other factors. Any ratio of the insectpoison and propynyl benzyl ether can be utilized as the active substance. However, it is preferred to use approximately one to ten parts by weight of a propynyl benzyl ether and approximately one to ten parts by weight of an insect-poison, with about equal parts by weight of the two components being especially preferred. i

Pest-control agents containing the combined insecticide composition in accordance with this'invention can be prepared in the form of granulates, concentrates or ready-to-use pest-control agents. The concentration of the insecticide composition depends upon the form of pest-control agent and the mode of use. The pestcontrol agents in accordance with this invention can contain solid or liquid carrier material to form solutions, sprays, aerosols or dusting powders, as set forth above with respect to the use of the propynyl benzyl ether with an inert carrier material.

In general, the pest-control agents utilizing the combined insecticide compositions of the present invention can be prepared according to a process such as is described, for example, in Farm Chemicals, vol. 128, pages 52 ff. The pest-control agents in accordance with this invention can additionally utilize yet other additives such as emulsifiers or masking agents.

The pest-control agents in accordance with this invention can exist in the form of concentrates which are suitable for storage and transport. Such concentrates can, for example, contain 40-80% by weight of the synergistically active combination of insect-poison and propynyl benzyl ether as the active substance and 6020% by weight of an inert carrier material. In preparing these concentrates, any conventional, liquid, or solid inert carrier material can be utilized. Among the inert carrier materials which can be utilized are the liquid solvents and solid materials mentioned above.

These concentrates can be further diluted with similar or different carrier materials to concentrations which are suitable for practical use as ready-to-u'se pest-control agents. In the ready-to-use agents, the active substance concentration is preferably 0.1-20 weight percent of the synergistically active substance and 99.9- weight percent of an inert carrier material, with 0.1-10 weight percent of the active substance and 99.9-9O weight percent of the inert carrier being especially preferred. The active substance concentration can also be smaller or larger than the preferred concentration. In preparing these ready-to-use pest-control agents, any conventional liquid or solid inert carrier material may be utilized. Among the inert carrier materials which may be utilized are the liquid and solid materials mentioned above.

The reaction of an alcohol of formula II with a halide of formula III, preferably a bromide, can be carried out in the presence of a base such as an alkali metal, an alkali metal amide or an alkali metal hydride. The preferred bases are the alkali metal hydrides, particularly sodium hydride. This reaction can be carried out in an inert organic solvent. In this reaction, any conventional, inert organic solvent can be utilized. Preferred solvents include dimethylformamide, dioxane and hexamethylphosphoric acid triamide. In this reaction, temperature and pressure are not critical, and the reaction can be caaried out at room temperature (22C.) and atmospheric pressure. Preferably the reaction is carried out at a temperature of 20C. to the reflux temperature of the reaction mixture, with about room temperature being particularly preferred.

The alcohol starting materials of formula II can be prepared in a simple and known manner either by reacting an aldehyde or ketone of the formula:

wherein R R R and R are as above;

with a Grignard compound of the formula:

R' -MgBr V wherein R is lower alkyl; or by reducing an aldehyde or ketone of formula IV with a complex metal hydride.

The compound of formula IV is conveniently reacted with the Grignard, lower alkyl magnesium halide of formula V under conventional conditions of temperature, pressure and absence of moisture. The Grignard product, which results, can be subsequently decomposed with ice-water in a conventional manner to yield the alcohol of formula 11.

The examples which follow illustrate the invention. All temperatures are in degrees Centigrade. Room temperature is about 22C. Unless otherwise stated, the ether solvent utilized is diethyl ether. The low-boiling petroleum ether utilized has a boiling point of 30 to 45C.

EXAMPLE 1 A solution of 16.6 g of 1,4-benzodioxan-o-methanol in 20 ml of dimethylformamide is added dropwise with stirring to a suspension of 12.5 g of sodium hydride in 75 ml of dimethylformamide. 11.8 g of propargyl bromide are then added dropwise. The mixture is stirred for 3 hours at room temperature, cooled in an ice-bath, decomposed with 20 ml of ice-water, diluted with 150 ml. of water and extracted three times with 150 ml of diethyl ether each time. The ether extract is washed with water, dried over sodium sulphate and evaporated. The oily residue is chromatographed on silica gel using benzene as the elution agent. There is obtained 6-[(2- propynyloxy)methyl]-1,4-benzodioxan; m, 1.5487.

EXAMPLE 2 Utilizing the procedure of Example 1, 1,3-benzodioxepine-7-methanol is converted to 3,4-dihydro-7-[(2- propynyloxy)methyl]-2H-1,S-benzodioxepine; m, 1.5811.

EXAMPLE 3 Utilizing the procedure of Example 1, piperonyl alcohol is converted to 3,4-methylenedioxy-a-(2- propynyloxy)-toluene; n,, 1.5409.

EXAMPLE 4 Utilizing the procedure of Example 1, veratryl alcohol is converted to 3,4-dimethoxy-a-(2-propynyloxy)- toluene; 11,, 1.5389.

EXAMPLE 5 A solution of 20.8 g of ot-ethylveratryl alcohol in 15 ml of dimethylformamide is added dropwise with stirring to a suspension of 12.5 g of sodium hydride in 75 ml of dimethylformamide. The mixture is stirred for 0.5 hour at room temperature (about 22C.), and l 1.8 g of. propargyl bromide are then added dropwise, the temperature not being allowed to exceed 30C. After stirring for 3 hours at room temperature, the mixture is cooled to an ice-bath to 5C., decomposed with icecold water at a temperature of approximately 15C. and extracted three times with 150 ml of diethyl ether. The extract is washed neutral with water, dried over sodium sulphate, filtered and the filtrate evaporated to dryness under reduced pressure. The oily residue is chromatographed on silica gel using benzene/ether (9:1 parts by volume) as the elution agent. There is obtained l,2-dimethoxy-4-[ l-(2-propynyloxy)propyl]- benzene; n,,'- 1.5248.

EXAMPLE 6 Utilizing the procedure of Example 5. methyl-3,4- dihydro-2H-l,5-benzodioxepineJ-methanol is converted to 3,4-dihydro-7-[1-(2-propynyloxy)propyl]- 2H-l.5-benzodioxepin; 11,, 1.5304.

EXAMPLE 7 Utilizing the procedure of Example 5, methyl-1,4- benzodioxan-6-methanol is converted to 6-[ l-(2- propynyloxy)propy1]-1,4-benzodioxan; 11,, 1.5336.

EXAMPLE 8 Utilizing the procedure of Example 5, a-ethylpiperonyl alcohol is converted to 1.2-methylenedi0xy-4-[l- (2-propynyloxy)propylI-benzene; 11,, 1.5256.

EXAMPLE 9 38.4 g of 3,4-dimethoxybenzyl-a-ethynyl alcohol are dissolved in 200 ml of ethyl acetate and hydrogenated in the presence of 1 g of Adams catalyst until no more hydrogen is taken up by the mixture. After completion of the hydrogenation, the catalyst is filtered off and the solvent completely evaporated. There remains behind a'ethylveratryl alcohol; b.p. 1 141 15C/O.5 mmHg.

EXAMPLE 1O Utilizing the procedure of Example 9, a-ethynylpiperonyl alcohol is converted to a-ethylpiperonyl alcohol; b.p. 101C/0.6 mml-lg.

EXAMPLE 1 l Utilizing the procedure of Example 9, a-ethynyl-l ,4- benzodioxan-6-methanol is converted to methyl-1,4- benzodioxan-o-methanol; b.p. 108C/0.02 mml-lg.

EXAMPLE 12 Utilizing the procedure of Example 9, a-ethynyl-3,4- dihydro-ZH-l,5-benzodioxepine-7-methanol is converted to a-ethyl-3,4-dihydro-2H-l,S-benzodioxepine- 7-methanol; b.p. 1 l5-116C/0.01 mmHg.

EXAMPLE 13 A solution of 5 g of a,a-diethylpiperonyl alcohol in 10 ml of tetrahydrofuran is added dropwise with stirring to a suspension of 2.5 g of sodium hydride in 25 ml of tetrahydrofuran. The mixture is then stirred for 1 hour at room temperature and thereafter treated dropwise with 6 g of propargyl bromide, the temperature being held below 30C. The mixture is cooled in an icebath, decomposed with ice-cold water and extracted with diethyl ether. The extract is washed neutral with water, dried over sodium sulphate, filtered and the filtrate evaporated to dryness. After chromatography on silica gel and elution with benzene, there is obtained a,a-diethylpipcronyl propargyl ether; m, 1.5291.

EXAMPLE 14 7.6 g of 3,4-methylenedioxy-propiophenone are dissolved in 40 ml of absolute diethyl ether and added under a nitrogen atmosphere to a Grignard solution prepared from 1.2 g of magnesium and 5.4 g of ethyl bromide in 15 ml of absolute diethyl ether. The mixture is heated at reflux for 1.5 hours and thenstirred at room temperature. The mixture is cooled in an ice-bath and decomposed by the addition of ice-water. Aconcentrated aqueous solution of ammonium chloride is then added, and the solution extracted twice with 500 ml of diethyl ether each time. The combined ether extracts are washed neutral with water, dried over sodium sulphate and evaporated to dryness. The residual oil is distilled and there is obtained colorless oz,a-diethylpiperonyl alcohol; b.p. l06l07C/O.65 mmHg.

EXAMPLE 15 g of a 50% (by weight) dispersion of sodium hydride in oil are washed free from oil with three portions of low-boiling petroleum ether and then added to 100 ml of dimethylformamide. 19.8 g of 3,4,5- trimethoxybenzyl alcohol are slowly added dropwise to the resulting mixture. The mixture thus obtained is stirred for 1 hour, and 18 g of propargyl bromide are then added dropwise thereto. The mixture is stirred for 1 hour, and the excess sodium hydride is decomposed by treatment with 200 ml of water. The mixture is extracted with 300 ml of diethyl ether, the ether extract is washed neutral, dried over sodium sulphate and evaporated. The residue is chromatographed on silica gel with benzene/ether (3:1 parts by volume). There is obtained 3,4,5-trimethoxy-a-(2-propynyloxy)-toluene which is distilled at 0.2 mmHg; b.p. 115C.

EXAMPLE 16 g of a 50% (by weight) dispersion of sodium hydride in oil are washed free from oil with three portions oEjow-boiling petroleum ether and then added to 75 ml of dimethylformamide. 13.8 g of p-methoxybenzyl alcohol are added dropwise to the resulting mixture over a period of 1 hour with stirring. After 1 hour, 1 1.8 g of propargyl bromide are added with stirring at such a rate that the temperature does not exceed 35-40C. The mixture is stirred at room temperature for a further 3 hours, then cooled in an ice-bath to O5C., and the excess sodium hydride decomposed with ice-water. After the addition of a further 100 ml. of water, the mixture is extracted three times with diethyl ether, the ether extract washed neutral with water, dried over sodium sulphate and evaporated. The residue is chromatographed on silica gel using methylene chloride as the elution agent. There is obtained p-methoxy-a-(Z- propynyloxy)-toluene; m, 1.5273.

EXAMPLE 17 25 g of a 50% (by weight) dispersion of sodium hydride in oil are washed free from oil with three portions of low-boiling petroleum ether and then added to 75 ml of absolute dimethylformamide. 14.2 g of pchlorobenzyl alcohol are addedportionwise to the resulting mixture with stirring over a period of 1 hour, and then 1 l .8 g of propargyl bromide are added so that the temperature does not exceed 35'40C. The mixture is stirred for a further 3 hours at room temperature and then cooled in an ice-bath to 05C. Water is cautiously added in order to decompose the excess sodium hydride. After the addition ofa further 100 ml of water, the mixture is extracted with diethyl ether; the ether extract washed neutral with three portions of water, dried over sodium sulphate and evaporated. The residue is chromatographedon silica gel-using methylene chlo ride as the elution agent. There is obtained pchlorobenzyl 2-propynyl ether; m, 1.5332.

EXAMPLE 18 30 g of a 50% (by weight) dispersion of sodium hydride oin oil are washed free from oil with three portions of low-boiling petroleum ether and then added to m1 of absolute dimethylformamide. Within 1 hour, 12.4 g of p-hydroxybenzyl alcohol are added to the resulting mixture with stirring. Thereafter, 30g of propargyl bromide are added dropwise over a period of 45 minutes at such a rate that the temperature does not exceed 3540C. The mixture is stirred for a further 3 hours at room temperature, and then the excess sodium hydride is decomposed by treatment with water. A fur ther 100 ml of water'are added, and the mixture is extracted three times with diethyl ether. The ether extract is washed neutral with water, dried over sodium sulphate, filtered and evaporated. The residue is chromatographed on silica gel using methylene chloride as the elution agent. There is obtained p-a-bis-(Z- propynyloxy)-toluene; n 1.5520.

EXAMPLE 19 25 g of a 50% (by weight) dispersion of sodium hydride in oil are washed free from oil with three portions of low-boiling petroleum ether and then added to 75 ml of absolute dimethylformamide. 12.2 g of pmethylbenzyl alcohol are added portionwise to this mixture, and the resulting mixture is stirred for 30 minutes. 1 1.8 g of propargyl bromide are added dropwise with stirring so that the temperature does not exceed 3540C. The mixture is stirred for 3 hours at room temperature, then cooled to 5C. in an ice-bath, and the excess sodium hydride decomposed by the addition of 25 ml of water. The mixture is diluted with a further 100 ml of water, extracted three times with diethyl ether, the ether extract washed neutral with water, dried over sodium sulphate and evaporated. The residue is chromatographed on silica gel using methylene chloride as the elution agent. There is obtained pmethylbenzyl 2-propynyl ether; n 1.5141.

EXAMPLE 20 g of a 50% (by weight) dispersion in oil are washed free from oil with three portions of low-boiling petroleum ether and then added to 75 ml of absolute dimethylformamide. 17.7 g of 3,4-dichlorobenzyl alcohol are added dropwise to the resulting mixture with stirring. After 30 minutes, 1 1.8 g of propargyl bromide are added dropwise with stirring at such a rate that the temperature does not exceed 3540C. The mixture is stirred at room temperature for a further 3 hours, then cooled in an ice-bath, and the excess sodium hydride decomposed by the addition of 25 ml of water. The mixture is diluted with a further ml of water, extracted three times with diethyl ether, the ether extract washed neutral with water, dried over sodium sulphate and evaporated. The residue is chromatographed on silica gel using methylene chloride as the elution agent. There is obtained 3,4-dichlorobenzyl 2-propynyl ether; n,, 1.5489.

The experiments described in the following examples are carried out with the following representative examples of the propynyl benzyl ethers (P) of formula I hav ing juvenile hormone-like activity, which can be uti= lized in combination with an insect-poison (1) to form dead or crippled are counted. The LD (based on inthe active substance for an insecticide composition. sect-poison) is calculated after 24 hours on the basis of A 3,4-(methylenedioxy)-a-(2-propynyloxy)-toluene the number of dead flies.

Table I1 LD concentration based on insect-poison FLlES P Sevin Methoxychlor Malathion Allethrin (lzP) (1:1 (1:1 (1:P) 1:5 100:0 :100 1:5 100:0 0:100 1:5 100:0 0:100 1:5 100:0 0:10

l Insect-poison. P Propynyl benzyl ether.

B 3,4-dimethoxy-a-(2-propynyloxy)-toluene EXAMPLE 23 The results for each example are provided in a table at the end thereof. The concentration for each LD determination is stated logarithmically in terms of the concentration of iSect-P015011 3 g/Cm3 For each test. three bean leaf discs each with a 2-day Spider-mites 1%0). Said LD values define the concentration of ini f ti and with 2 4 spidepmites and eggs are Sect-P0150n p at whlch 50% of the mlsectsple or sprayed with a solution of the active ingredient(s) in become crippled. In the case where the ratio of msectacetone or an aqueous spmy wash f the active Poison to p p benzyl ether 15 0:100 (LP 03100) gredient(s). The dosage for each treated surface is 10 the so Values Stated refer to the p py y benzyl glcm =l kg/ha. After 2 days, the discs are assessed for ether itself (and are not based on the insect-poison). dead spidepmites and after 6 days for dead Spider EXAMPLE 21 mites and killed eggs. (Assessment scheme: from 05,

. where 0 0% and 5 100% mortality). Aphlds W Assessment based on the mortality of the spider- For each test, one seedling of the field bean with ca mi 50-100 black bean aphids is sprayed with a solution of O assessment based on the mortality of the eggs.

Table 111 1:5 100:0 0:100 1:5 100:0 0:100 1:5 100:0:100115 100:0 0:100 WOWOWOWOWOWOWWWWOWOWO l Insect-poison. P Propynyl benzyl ether.

the active ingredient(s) in acetone or an aqueous We claim:

spray-wash of the active ingredient(s). The seedlings 1. An insecticide composition comprising from 0.01 are individually placed in tubes in water. After 24 and to 0.05 of a propynyl benzyl ether of the formula:

48 hours, the dead and surviving aphids are counted and the activity calculated in Ra 50 Table l C OCH C i CH LD concentration based on insect-poison R. APHIDS P Methoxychlor Malathion Allethrin 1 1 (l:P) (lzP) (IzP) R 1:5 100:0 0:100 1:5 100:0 0:100 1:5 100:0 0:100

wherein R is hydrogen; R is propynyloxy; R and R A 4.5 3.3 3.0 5.7 5.0 3.0 B 5A1 are hydrogen or lower alkyl; and R is hydrogen; I: ,mcbpnimm and an inert carrier material. I P py yl enz l ether. 2. The composition of claim 1, wherein said composition includes an additional insect-poison. EXAMPLE 22 3. The composition of claim 2 wherein said composi- Flies tion comprises 1 to 10 parts by weight of said insect- For each test, two petri dishes are sprayed with a sopoison and 1 to 10 parts by weight of said propynyl lution of the active ingredient(s) in acetone or an aquebenzyl ether. ous spray-wash of the active ingredient(s). The dosage 4. A process for protecting materials from insects sefor each treated surface is 10 g/cm l kg/ha. After lected from the group consisting of Diplera, Lepidop- 2-3 hours, 10 flies aged 4-5 days are placed in each tera Coleoptera and Prodenia litum comprising applying petri di h. After 1. 3 nd 24 h ur h f ie which re to said material an effective amount for killing and the prevention of proliferation of said insects of a comh i R i hydrogen; R is propynyloxy; R and R Pound of the formulai are hydrogen or lower alkyl; and R is hydrogen.

5. The process of claim 4 wherein said compound is CH 5 applied in an amount sufficient to supply from about i to 10 grams per cm of said material to be pro- R4 tected. 

1. AN INSECTICIDE COMPOSITION COMPRISING FROM 0.01 TO 0.05 OF A PROPYNL BENZYL ETHER OF THE FORMULA:
 2. The composition of claim 1, wherein said composition includes an additional insect-poison.
 3. The composition of claim 2 wherein said composition comprises 1 to 10 parts by weight of said insect-poison and 1 to 10 parts by weight of said propynyl benzyl ether.
 4. A process for protecting materials from insects selected from the group consisting of Diptera, Lepidoptera Coleoptera and Prodenia litura comprising applying to said material an effective amount for killing and the prevention of proliferation of said insects of a compound of the formula:
 5. The process of claim 4 wherein said compound is applied in an amount sufficient to supply from about 10 3 to 10 6 grams per cm2 of said material to be protected. 